From: Joerg Hansmann (jhansmann_at_g...)
Date: 2000-11-30 15:58:03
Hi yaniv,
----- Original Message -----
From: <yaniv_vi_at_yahoo.com>
To: <buildcheapeeg_at_egroups.com>
Sent: Thursday, November 30, 2000 9:13 AM
Subject: [buildcheapeeg] Re: hi folks
> if you want to make it simple - it doesn't have to be true irda .
> the first version of the desing could be consisted of 2 boxes :
> one is the eeg with simplest infrared comm , and the other is just
> little thing that connects to parallel port/serial port , with infra
> red com .
If you think of IR-receiver ICs like the TSOP17xx series, you should
consider, that maximum data rate is 2400 baud (from Vishay TSOP17.pdf
datasheet ). That is far below the 57600 baud required by RS232EEG.
Using a simple PIN-IR-receiver diode will work only over very short
distances (some cm).
BTW. what distance will we need ?
> i don't think that would higher the price much.
> and the design is basicly already there (on the net).
A complete schematic for an irda transceiver that can be connected
to RS232 and can handle up to 115200 baud is described here:
http://www.vishay.com/pdf/toim3232.pdf
However it uses two SMD chips and I don't know, how easy or difficult
soldering will be.
> just for the 1st version i think it'll be good.
> after the first version if all we'll be o.k. then i'll think we could
> work on better version easier - because we'll probably have more
> people .
> but maybe full irda is better , i don't know ?
> > > ) and
> > > with right box ( plastik with metal foil) we'll be safe enough
> >
> > The FDA probably wont think so before they have approved the device.
> >
>
> there's a eeg device called waverider - sells for $950 without fda
> approval -
Perhaps they have a good lawyer or a good product liability insurance.
> and it's presented in futurehealth site - a very
> respectable site for this things .
> and another thing - i agree we should check it with some b.f.
> practicioner maybe - or somebody that will check .
> maybe somebody should check what it takes to run throught an
> fda - and how much it'll cost for a gruop of volunteers ,
> and if it's possible to be done by a group of volunteers ?
> but i don't really think fda approval is a must .
> i just thjink we should really check it with someone experienced
> before getting it to market - maybe some b.f. practicioner would
> volunteer -if we'l find one .
...
[patents]
> > The overall principle is the same.
>
> there have been numerous designes basicly the same .
> i don't really think there's a problem ,but i guess it's better to
> check , and as i seen in our group we may have contacts to a lawyer -
> so it'll be o.k.
...
> a little question joerg :
> assuming i want to be the first beta tester - let's say even of the
> version without irda - just a good version for portable pc (no need
> of isolation)
The current prototype _is_ isolated with optoisolators. (The BM also
uses optoisolators for RS232).
> would like to build one board and send it to me - i'll pay the
> costs ? how much are the costs ?
Material cost (without casing) is about 200,- DM.
shipping and insurance = ? (depends on the destination)
Can you make money transfer to a german bank ?
(When I tried to make a transfer from Germany to USA,
I found out, that the banking fees are extremely high)
Do you need casing or the raw assembled pcb ?
What about RS232 cable ? What length ?
What about power supply ?
If your laptop had a gameport-connector, +5V from your laptop
could be used. However I don't know how much noise
is on that line.
Do you have the possibility to get +12V DC from your laptop ?
In this case the built in 7805 regulator could be used and line noise
would not be a problem.
What connectors/sockets for electrodes are required ?
(banana sockets ? (in german : Bananenbuchse))
or better BNC or cinch ?
I don't know the standard for eeg-electrodes...
BTW. Where can I get good and low-priced EEG-electrodes ?
> when it'll be ready stable enough
> version of the h.w. - tested and tested in really measuring
> brainwaves ?
I have sampled real brainwaves with the RS232EEG and tried
some alpha-feedback with Rob's Software.
What are your demands for stability and tested in detail ?
> the software i can always download from the net , so no problem .
>
> basicly my problem that my friend in israel that was supoosed to
> build brainmaster and send it to me - hasn't got the time - and also
> not very serious about it , so basicly i think he won't build it .
>
> i'm intend to find a buddhist lama here that would like to work with
> me using eeg and other buddhist techniques , so it may be also good
> for the public realtions of the project ?
Sounds nice. I am really interested in samples of brainwaves of a meditating
lama. Perhaps Rob could add the feature of recording / viewing
eeg-data files.
regards
Joerg
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